As per the subject, is anyone running Windows 8 on the same hardware where Windows 7 was installed before, and if so any noticeable performance improvements - startup, shutdown, sleep, hibernate, resume, etc?

Found it starts much quicker, closes quicker, runs very nicely in general. Hibernate works well although there have been a few weird instances where Ive come along in the morning to find the comp running again - Im thinking Windows Updates though.

Startup (with more or less the same stuff running on my Win8 install as I had on my Win7) is like a min tops compared to 3-4 before - thats from turn on to desktop.

Newish Toshiba Techra 850 and same as above comments, if anything seems faster. One noticable difference that surprised me was the shared Graphics performs so much better on Windows 8, don't understand why but it does. The tiles do seem to take what seems like forever to open but that may be normal.

askelon: Found it starts much quicker, closes quicker, runs very nicely in general. Hibernate works well although there have been a few weird instances where Ive come along in the morning to find the comp running again - Im thinking Windows Updates though.

Startup (with more or less the same stuff running on my Win8 install as I had on my Win7) is like a min tops compared to 3-4 before - thats from turn on to desktop.

Application opening etc is noticeably quicker as well. Don't see the occasional stutter when opening a program that I'd see with Win 7.

My work machine is slightly older and lesser specced than my gaming one and the difference I feel is phenomenal and I did an upgrade for that one. Programs like Photoshop CS6 open in a fraction of the time they did on Win 7.

I find that with Fast Startup, Windows 8 starts up faster, but shut down is delayed a little bit as it writes down the kernel state onto disk.

Disabling it, Windows 8 still feels slightly faster during start up (prior to login) than Windows 7, but the "blank" state from startup to login takes ages (on my system at least.) Shut down in this case is comparable to Windows 7.

Sleep is about the same for me - though I believe driver issues cause my keyboard and trackpad to partially respond upon wake for a couple of seconds which is annoying.

Overall general application performance doesn't feel any different from my perspective.

I have installed Windows 8 on older "Vista capable" machines that were running Windows 7 and the performance improvement is night and day. Also the drivers that came with the installer seem to have better coverage overall. There is less difference of improvement over newer hardware.

Running on my work desktop and having installed it on a number of work laptops now, it seems faster and smoother than windows 7. The laptops are vista spec machines with 4gb ram and the desktops are AMD athlon systems with 6+ gb ram. Not done enough of the I7 dev desktops yet to comment. How much of this is win 8 and how much is that it is a clean install, I am not sure. I also think Microsoft have really done some good work tuning the animations so everything seems to be smooth and have a flow to it even on low spec graphics hardware.

i7 2600k, 8GB DRR3-1600, SSD. Boot times were vastly improved. I don't ever remember sleeping or hibernating the machine so I can't comment. But most things were generally quicker. I have gone back to Windows 7 because of personal preference. However, I'll be updating again soon I feel.